HomeMy WebLinkAbout2012-08-08 PACKET 08.C.City of
Cotta Grove
Minnesota
To:
Parks, Recreation and Natural Resources Commission
From:
Zac Dockter, Parks and Recreation Director
CC:
Date:
July 24, 2012
Subject:
Japanese Beetle
In light of the recent spread of the Japanese Beetle, the City Forester has been fielding an abundance
of calls and concerns regarding this pest and the damaging effects it is having on trees in the
community. In an effort to promote understanding, Steve has put together a press release explaining
more about the beetle, its impacts and treatment /control options. That press release is attached for
your review. This information will be shared through multiple media outlets and there will also be a
short video segment on some of the local cable television programming.
What's eating my trees and shrubs?
If you have a Linden, Birch or Elm tree or a variety of other landscape trees and
shrubs, the most likely answer is the Japanese beetle.
Within the past few years, we have seen mild frost conditions and the result of
this is a spike in the population of the Japanese beetle. During a typical winter,
frost kills the beetle in the larvae stage. The Japanese beetle is a non - native
insect that feeds on leaves as an adult and also lives in the soil as a grub.
Feeding off the tree leaves causes a "skeleton" look to the leaves once they fall
off. As the beetle feeds on the leaves, they die and fall to the ground. This
feeding first will occur in the upper canopy, and then will move to the lower
canopy as the infestation increases. This feeding does not kill the tree, however
will cause defoliation.
If trees do not re- foliate this year, they definitely should this spring. When
dealing with young trees, it's a good idea to continue to water the tree so that
drought doesn't increase the stress level. As a grub, the insect will feed on the
grass roots of your yard. If there is a large population of grubs in the soil, they
can kill the grass. The adult beetles will conclude feeding in late July and in early
August will start to breed, lay eggs in the soil, and finally, die.
What should 1 do to help control the Japanese Beetle population and /or save my
plants from getting eaten?
One options is to do nothing since the beetles don't actually kill any plants and
are only out for a short time in the summer.
The next option, (depending on the amount of time and money you want to
invest) is to either use a spray intended for landscape plants, use a bag
attractant to capture the adult beetle, or utilize soil treatments to keep your yard
and trees healthy. If you choose a soil treatment for your trees, a certified
arborist or a tree service company can help with this option. Homeowners can
also apply a grub control to their lawn. While some sprays can be applied by the
homeowner, a tree service can be consulted to spray larger trees and shrubs.
Many options are out there, some better than others. As a homeowner, the best
method may be to use a grub control in the yard because the larvae are easier to
control since the adult beetles have the ability to fly.
What is the City of Cottage Grove doing to control the Japanese beetle?
The City of Cottage Grove has done some grub control in City Parks during the
spring and fall to help keep the numbers down in these areas. The City of
Cottage Grove is relying on the homeowner to help reduce the Japanese beetle
population throughout the neighborhoods. If the homeowner does some type of
control method for their landscape trees and shrubs, it will help reduce the effects
of the pest on the boulevard trees. It is a pesky pest to control and with the help
of homeowners (and a little help from Mother Nature) we'll hopefully see the
decrease in Japanese beetle population numbers in years to come.